Is there a way to make a shortcut comment the current line?
You could create a custom operator and map the following to a shortcut.

bpy.ops.text.move(type='LINE_BEGIN')
bpy.ops.text.insert(text="#")


or if selecting the line is tiresome you can just automate the selection step then comment

bpy.ops.text.select_line()
bpy.ops.text.comment_toggle()


Creating a custom operator would look something like this

import bpy

class CommentLineOperator(bpy.types.Operator):
    bl_idname = 'text.comment_line'
    bl_label = 'Comment a line'

    def execute(self, context):
        bpy.ops.text.select_line()
        bpy.ops.text.comment() &gt;&gt; bpy.ops.text.comment_toggle() since 2.8

        return {'FINISHED'}

bpy.utils.register_class(CommentLineOperator)
bpy.utils.unregister_class(CommentLineOperator)


After that, you should be able to map a shortcut easily to text.comment_line.

To have this load at startup, just save it with a .py extension and drop it into your scripts/startup/ folder. See How could a single Python script run when Blender is started?.